Are you hearing a screech or squeal when you brake? Your brake pads may be sending a warning. Whether yours are semi-metallic, ceramic, or organic, your vehicle likely has brake pads with wear indicators that alert you when it’s time for replacement.
These “squealers” on your brake pads are a simple but vital feature for brake maintenance. Keep reading to learn what brake wear indicators are, how brake wear sensors work, and how to know when to change your pads.
What Are Brake Wear Indicators?
A brake wear indicator is a built-in safety feature that signals when pads are worn and need replacing. Brake pads wear down over time because the friction material they use to squeeze and slow your brake rotors eventually thins out from use.
Most pads reach a minimum thickness of about 2 mm before the indicator alerts you. This gives you time to replace them before braking performance, stopping power, and safety are compromised.
Vehicles with disc brakes typically have two pads per wheel—one on each side of the rotor. Drum brakes use two brake shoes per drum. Depending on your brake system, the wear indicator will either make an audible squeal or trigger a dashboard warning light.
Acoustic Brake Wear Indicators
Also known as squealers, acoustic brake wear indicators use thin metal tabs that are attached to the pads. When the pad material wears low, the tab contacts the rotor, creating a high-pitched squeal when braking.
Instead of disc brakes with pads, your car might have drum brakes with brake shoes on the rear wheels. Brake shoes typically use an acoustic brake wear indicator in much the same way. However, not all brake shoes use a squealer. It’s always best to have your brakes inspected at the manufacturer's suggested mileage intervals.
What Does a Brake Wear Indicator Sound Like?
Brake wear indicators make a sharp, consistent squeal that occurs every time you apply the brakes. But that annoying screech isn’t a flaw—it’s a feature meant to remind you to get your brakes back in working order.
If you recently replaced your brake pads and are still hearing a squeal, it could be from some lingering break-in as the pads conform to your rotors.
Electronic Brake Wear Sensors
More modern wear indicators use an electronic brake wear sensor that sends warning lights to your dashboard when your brake pads reach minimum thickness. Electronic brake pad wear sensors typically come as either one or two-stage sensors embedded in the brake pad.
In one-stage sensors, the worn brake pad eventually exposes a wire that contacts the metal rotor, triggering an electrical signal that illuminates a warning light on your dashboard. A two-stage brake wear sensor gets a little more advanced.
Two-stage sensors use parallel circuits embedded at different depths of the brake pad. When the first circuit breaks, the sensor begins recording data such as mileage and brake temperature to calculate how much life is left in the pad. That data is relayed to you on the dashboard to keep you informed on the health of your brake pads. Then, once the second circuit breaks, a full warning light illuminates on your dashboard to tell you your brake pads are worn out.
How to Know When to Change Brake Pads
You’ll know it’s time to change your brake pads or have your braking system inspected by a professional technician when you hear the squealers or get warning lights on your dashboard.
Other Reasons Your Brakes Might Be Squeaking
Not every screech or squeal from your brakes means you have worn brake pads. Some squealing noises may be due to:
- Moisture on the brake rotors from wet road conditions
- Rust forming on the rotors
- Dust and debris between the pads and rotors or drums and shoes
- Improper brake pad installation
Fortunately, most of these issues work themselves out with regular brake pad use. If you suspect your brake pads may have been installed improperly or you’re troubleshooting issues like a grinding sound coming from your brakes, don’t wait to get your brakes checked.
Brake Wear Indicator FAQs
Do All Brake Pads Have Squealers?
No. While acoustic brake pads or “squealers” are common, many brake pads now use electronic sensors that trigger a dashboard warning light when your brake pads reach minimum thickness.
How Do You Know When You Need New Brakes?
The best way to know if you need new brakes is to check them regularly. While wear indicators like squealers and dashboard alerts can help you stay on top of brake pad replacement, there’s a lot more that goes into maintaining a safe and responsive brake system.
At Firestone Complete Auto Care, we offer free brake inspections with your visit. Our expert technicians will test your brakes, check brake fluid levels, inspect critical components, and more to help you determine if any maintenance is needed.
What is a Brake Pad Wear Indicator?
A brake wear indicator is a safety mechanism built into your brake pads or shoes that alerts you when they are worn down and need replacing.
How Do You Check Brake Pad Wear Indicators?
Acoustic indicators can be heard when braking. For electronic systems, your dash light will alert you. You can also stop by your local Firestone Complete Auto Care and have your braking system inspected today.
How Long Can You Drive With a Brake Wear Indicator Warning?
Not long. Wear indicators are designed to give you a short grace period before the pads wear down completely. Delaying pad replacement can damage your brake rotors or other braking components like calipers and compromise your ability to brake safely.
Should You Replace All Your Brake Pads at Once?
To ensure even braking performance, all pads or shoes per axle (front or rear) are replaced during a brake service. It is not required to replace the pads or shoes of the opposite axle if those components are not worn out. For example, if the brake inspection reveals that your vehicle needs front brakes, it is not required to replace the rear brakes unless they are also worn out. Most cars experience the brunt of the braking force at the front wheels, so your front brake pads may need replacing sooner than the pads on your rear wheels.
How Easy is it to Replace Your Own Brake Pads?
For savvy home mechanics, replacing your own brake pads is doable with the right tools and safety precautions. For everyone else, it’s best not to leave your safety to chance. Let the pros at Firestone Complete Auto Care replace your brake pads and feel confident in your ability to brake in the blink of an eye.
Listen to Your Brakes—and the Pros at Firestone Complete Auto Care
If you’re hearing from your brakes, it could be your brake pad wear indicators telling you it’s time for a change. Don’t wait until that squeal turns into a grinding issue—Firestone Complete Auto Care’s expert technicians can inspect your brakes and replace worn pads to keep you safe on the road. Schedule your appointment today or stop by your nearest location!
